Peak season isn't one day. That's like picking one day in May statistically as the "peak" of tornado season, but in any given year the biggest outbreak is just as likely to happen a few days, or 2-3 weeks before or after (or in mid-December, lol).
IMO peak hurricane season is August 20th through the end of September, with a watchful eye remaining on the Caribbean/Gulf through the end of October (Opal, Mitch, Wilma, Sandy, Michael).
Back-to-back years the most significant storms, Joaquin and Matthew formed on 9/28. Maria hit PR on 9/20.
I wasn't tracking the season closely in 2013 because I had a lot of stuff going on in A/S/O that year (move and new job) so it was more like at some point I went "Huh, haven't heard of any significant hurricanes going on in the Atlantic; I thought they predicted a busy season, guess they were wrong," but after this year I'm throwing in the towel on the utility of pre-season indicators/activity forecasts. Entertainment value only.
Not that there couldn't still be a major hurricane or two, perhaps a significant, destructive one, in later September or October (just like some of those I mentioned above), but those expert forecasts explicitly called for an active August and/or a dangerous setup for long-tracking MDR cyclones (the creme de la creme, the Ivans, Irmas, etc).